SynonymPostList Class Reference

A postlist comprising several postlists SYNONYMed together. More...

#include <synonympostlist.h>

Inheritance diagram for SynonymPostList:

Collaboration diagram for SynonymPostList:

List of all members.

Public Member Functions

SynonymPostList (PostList *subtree_, MultiMatch *matcher_)

~SynonymPostList ()

void set_weight (const Xapian::Weight *wt_)

Set the weight object to be used for the synonym postlist.

PostList * next (Xapian::weight w_min)

Advance the current position to the next document in the postlist.

PostList * skip_to (Xapian::docid did, Xapian::weight w_min)

Skip forward to the specified docid.

Xapian::weight get_weight () const

Return the weight contribution for the current position.

Xapian::weight get_maxweight () const

Return an upper bound on what get_weight() can return.

Xapian::weight recalc_maxweight ()

Recalculate the upper bound on what get_weight() can return.

Xapian::termcount get_wdf () const

Return the wdf for the document at the current position.

Xapian::doccount get_termfreq_min () const

Get a lower bound on the number of documents indexed by this term.

Xapian::doccount get_termfreq_est () const

Get an estimate of the number of documents indexed by this term.

Xapian::doccount get_termfreq_max () const

Get an upper bound on the number of documents indexed by this term.

Xapian::docid get_docid () const

Return the current docid.

Xapian::termcount get_doclength () const

Return the length of current document.

bool at_end () const

Return true if the current position is past the last entry in this list.

Xapian::termcount count_matching_subqs () const

Count the number of leaf subqueries which match at the current position.

std::string get_description () const

Return a string description of this object.

Private Attributes

PostList * subtree

The subtree, which starts as an OR of all the sub-postlists being joined with Synonym, but may decay into something else.

MultiMatch * matcher

The object which is using this postlist to perform a match.

const Xapian::Weight * wt

Weighting object used for calculating the synonym weights.

bool want_doclength

Flag indicating whether the weighting object needs the doclength.

bool want_wdf

Flag indicating whether the weighting object needs the wdf.

bool have_calculated_subtree_maxweights

Flag indicating if we've called recalc_maxweight on the subtree yet.

Detailed Description

A postlist comprising several postlists SYNONYMed together.

This postlist returns all postings in the OR of the sub postlists, but returns weights as if they represented a single term. The term frequency portion of the weight is approximated.

Definition at line 34 of file synonympostlist.h.

Constructor & Destructor Documentation

SynonymPostList::SynonymPostList	(	PostList *	subtree_,
		MultiMatch *	matcher_
	)			`[inline]`

Definition at line 60 of file synonympostlist.h.

SynonymPostList::~SynonymPostList ( )

Definition at line 30 of file synonympostlist.cc.

References subtree, and wt.

Member Function Documentation

bool SynonymPostList::at_end ( ) const [virtual]

Return true if the current position is past the last entry in this list.

Implements Xapian::PostingIterator::Internal.

Definition at line 146 of file synonympostlist.cc.

References Xapian::PostingIterator::Internal::at_end(), LOGCALL, RETURN, and subtree.

Xapian::termcount SynonymPostList::count_matching_subqs ( ) const [virtual]

Count the number of leaf subqueries which match at the current position.

Reimplemented from Xapian::PostingIterator::Internal.

Definition at line 152 of file synonympostlist.cc.

std::string SynonymPostList::get_description ( ) const [virtual]

Return a string description of this object.

Implements Xapian::PostingIterator::Internal.

Definition at line 158 of file synonympostlist.cc.

References Xapian::PostingIterator::Internal::get_description(), and subtree.

Xapian::docid SynonymPostList::get_docid ( ) const [virtual]

Return the current docid.

Implements Xapian::PostingIterator::Internal.

Definition at line 134 of file synonympostlist.cc.

References Xapian::PostingIterator::Internal::get_docid(), LOGCALL, RETURN, and subtree.

Xapian::termcount SynonymPostList::get_doclength ( ) const [virtual]

Return the length of current document.

Implements Xapian::PostingIterator::Internal.

Definition at line 140 of file synonympostlist.cc.

References Xapian::PostingIterator::Internal::get_doclength(), LOGCALL, RETURN, and subtree.

Referenced by get_weight().

Xapian::weight SynonymPostList::get_maxweight ( ) const [virtual]

Return an upper bound on what get_weight() can return.

Implements Xapian::PostingIterator::Internal.

Definition at line 89 of file synonympostlist.cc.

References Xapian::Weight::get_maxpart(), LOGCALL, RETURN, and wt.

Referenced by recalc_maxweight().

Xapian::doccount SynonymPostList::get_termfreq_est ( ) const [virtual]

Get an estimate of the number of documents indexed by this term.

It should always be true that: get_termfreq_min() <= get_termfreq_est() <= get_termfreq_max()

Implements Xapian::PostingIterator::Internal.

Definition at line 122 of file synonympostlist.cc.

References Xapian::PostingIterator::Internal::get_termfreq_est(), LOGCALL, RETURN, and subtree.

Xapian::doccount SynonymPostList::get_termfreq_max ( ) const [virtual]

Get an upper bound on the number of documents indexed by this term.

Implements Xapian::PostingIterator::Internal.

Definition at line 128 of file synonympostlist.cc.

References Xapian::PostingIterator::Internal::get_termfreq_max(), LOGCALL, RETURN, and subtree.

Xapian::doccount SynonymPostList::get_termfreq_min ( ) const [virtual]

Get a lower bound on the number of documents indexed by this term.

Implements Xapian::PostingIterator::Internal.

Definition at line 116 of file synonympostlist.cc.

References Xapian::PostingIterator::Internal::get_termfreq_min(), LOGCALL, RETURN, and subtree.

Xapian::termcount SynonymPostList::get_wdf ( ) const [virtual]

Return the wdf for the document at the current position.

The default implementation throws Xapian::UnimplementedError.

Reimplemented from Xapian::PostingIterator::Internal.

Definition at line 110 of file synonympostlist.cc.

References Xapian::PostingIterator::Internal::get_wdf(), LOGCALL, RETURN, and subtree.

Referenced by get_weight().

Xapian::weight SynonymPostList::get_weight ( ) const [virtual]

Return the weight contribution for the current position.

Implements Xapian::PostingIterator::Internal.

Definition at line 64 of file synonympostlist.cc.

References get_doclength(), Xapian::Weight::get_sumpart(), get_wdf(), LOGCALL, RETURN, want_doclength, want_wdf, and wt.

PostList * SynonymPostList::next ( Xapian::weight w_min ) [virtual]

Advance the current position to the next document in the postlist.

The list starts before the first entry in the list, so next() must be called before any methods which need the context of the current position.

Parameters:

w_min

The minimum weight contribution that is needed (this is just a hint which PostList subclasses may ignore).

Returns:: If a non-NULL pointer is returned, then the caller should substitute the returned pointer for its pointer to us, and then delete us. This "pruning" can only happen for a non-leaf subclass of this class.

Implements Xapian::PostingIterator::Internal.

Definition at line 46 of file synonympostlist.cc.

References LOGCALL, matcher, next_handling_prune(), RETURN, and subtree.

Xapian::weight SynonymPostList::recalc_maxweight ( ) [virtual]

Recalculate the upper bound on what get_weight() can return.

If the tree has pruned, get_maxweight() may use cached values. Calling this method instead forces a full recalculation.

Note that this method may be called after the postlist has reached the end. In this situation, the method should return 0.

Implements Xapian::PostingIterator::Internal.

Definition at line 96 of file synonympostlist.cc.

References get_maxweight(), have_calculated_subtree_maxweights, LOGCALL, Xapian::PostingIterator::Internal::recalc_maxweight(), RETURN, and subtree.

void SynonymPostList::set_weight ( const Xapian::Weight * wt_ )

Set the weight object to be used for the synonym postlist.

Ownership of the weight object passes to the synonym postlist - the caller must not delete it after use.

Definition at line 37 of file synonympostlist.cc.

References Xapian::Weight::get_sumpart_needs_doclength_(), Xapian::Weight::get_sumpart_needs_wdf_(), want_doclength, want_wdf, and wt.

PostList * SynonymPostList::skip_to	(	Xapian::docid	,
		Xapian::weight	w_min
	)			`[virtual]`

Skip forward to the specified docid.

If the specified docid isn't in the list, position ourselves on the first document after it (or at_end() if no greater docids are present).

Parameters:

w_min

The minimum weight contribution that is needed (this is just a hint which PostList subclasses may ignore).

Returns:: If a non-NULL pointer is returned, then the caller should substitute the returned pointer for its pointer to us, and then delete us. This "pruning" can only happen for a non-leaf subclass of this class.

Implements Xapian::PostingIterator::Internal.

Definition at line 55 of file synonympostlist.cc.

References LOGCALL, matcher, RETURN, skip_to_handling_prune(), and subtree.

Member Data Documentation

bool SynonymPostList::have_calculated_subtree_maxweights [private]

Flag indicating if we've called recalc_maxweight on the subtree yet.

Definition at line 57 of file synonympostlist.h.

Referenced by recalc_maxweight().

MultiMatch* SynonymPostList::matcher [private]

The object which is using this postlist to perform a match.

This object needs to be notified when the tree changes such that the maximum weights need to be recalculated.

Definition at line 45 of file synonympostlist.h.

Referenced by next(), and skip_to().

PostList* SynonymPostList::subtree [private]

The subtree, which starts as an OR of all the sub-postlists being joined with Synonym, but may decay into something else.

Definition at line 38 of file synonympostlist.h.

Referenced by at_end(), get_description(), get_docid(), get_doclength(), get_termfreq_est(), get_termfreq_max(), get_termfreq_min(), get_wdf(), next(), recalc_maxweight(), skip_to(), and ~SynonymPostList().

bool SynonymPostList::want_doclength [private]

Flag indicating whether the weighting object needs the doclength.

Definition at line 51 of file synonympostlist.h.

Referenced by get_weight(), and set_weight().

bool SynonymPostList::want_wdf [private]

Flag indicating whether the weighting object needs the wdf.

Definition at line 54 of file synonympostlist.h.

Referenced by get_weight(), and set_weight().

const Xapian::Weight* SynonymPostList::wt [private]

Weighting object used for calculating the synonym weights.

Definition at line 48 of file synonympostlist.h.

Referenced by get_maxweight(), get_weight(), set_weight(), and ~SynonymPostList().

The documentation for this class was generated from the following files:

matcher/synonympostlist.h
matcher/synonympostlist.cc


Public Member Functions
	SynonymPostList (PostList subtree_, MultiMatch matcher_)
	~SynonymPostList ()
void	set_weight (const Xapian::Weight *wt_)
	Set the weight object to be used for the synonym postlist.
PostList *	next (Xapian::weight w_min)
	Advance the current position to the next document in the postlist.
PostList *	skip_to (Xapian::docid did, Xapian::weight w_min)
	Skip forward to the specified docid.
Xapian::weight	get_weight () const
	Return the weight contribution for the current position.
Xapian::weight	get_maxweight () const
	Return an upper bound on what get_weight() can return.
Xapian::weight	recalc_maxweight ()
	Recalculate the upper bound on what get_weight() can return.
Xapian::termcount	get_wdf () const
	Return the wdf for the document at the current position.
Xapian::doccount	get_termfreq_min () const
	Get a lower bound on the number of documents indexed by this term.
Xapian::doccount	get_termfreq_est () const
	Get an estimate of the number of documents indexed by this term.
Xapian::doccount	get_termfreq_max () const
	Get an upper bound on the number of documents indexed by this term.
Xapian::docid	get_docid () const
	Return the current docid.
Xapian::termcount	get_doclength () const
	Return the length of current document.
bool	at_end () const
	Return true if the current position is past the last entry in this list.
Xapian::termcount	count_matching_subqs () const
	Count the number of leaf subqueries which match at the current position.
std::string	get_description () const
	Return a string description of this object.
Private Attributes
PostList *	subtree
	The subtree, which starts as an OR of all the sub-postlists being joined with Synonym, but may decay into something else.
MultiMatch *	matcher
	The object which is using this postlist to perform a match.
const Xapian::Weight *	wt
	Weighting object used for calculating the synonym weights.
bool	want_doclength
	Flag indicating whether the weighting object needs the doclength.
bool	want_wdf
	Flag indicating whether the weighting object needs the wdf.
bool	have_calculated_subtree_maxweights
	Flag indicating if we've called recalc_maxweight on the subtree yet.